Fenerbahce said that Skriniar will receive an annual salary of 8.0 million euros. The transfer fee was not disclosed.
Skriniar moved to the Istanbul-based club on loan from PSG in January before the move was made permanent on Thursday.
"Milan Skriniar... has completed a permanent move to Fenerbahce SK in Türkiye," PSG said in a statement.
The 30-year-old Skriniar, who joined PSG from Serie A club Inter Milan in 2023, helped Fenerbahce to finish second in the Turkish top flight last season.
Fenerbahce are managed by Jose Mourinho